1. Field of the Invention
The present disclosure is directed to a transflective liquid crystal display devices that are capable of improving light efficiency and methods of fabricating the same.
2. Description of the Related Art
Liquid crystal display (“LCD”) devices control light transmission characteristics of liquid crystal materials with electric fields to display pictures. An LCD device has an LCD panel having a sandwich-like structure with liquid crystal molecules interposed between two substrates. In VA (Vertical Alignment) mode, two substrates have electrodes facing each other. The liquid crystal molecules are rotated by an electric field generated when a voltage is applied across the electrodes.
An LCD device requires a light source and is broadly classified into a transmissive type and a reflective type, depending on which light source is used.
A transmissive LCD device displays images by using light emitted from a backlight lamp positioned at the rear of the LCD panel. On the other hand, a reflective LCD device uses ambient light, such as external illumination or sunlight.
The transmissive LCD device is useful in dark environments since a backlight lamp is provided, however, it consumes a large amount of power. On the other hand, the reflective LCD device using ambient light has low power consumption, but viewing is difficult in dark rooms or at night.
A transflective LCD device is useful in both bright and dark environments. The transflective LCD device operates as the transmissive LCD device using the backlight lamp in a bright ambient light environment and operates as the reflective LCD device in a dark ambient light environment.
FIGS. 1 and 2 are partial cross sectional views illustrating a conventional transflective LCD device operating in a reflective mode and in a transmissive mode, respectively.
In FIGS. 1 and 2, left parts (a) of an LCD device 100 show an operation of the LCD device 100 when a driving voltage is not applied to a liquid crystal layer, and right parts (b) of LCD device 100 show an operation of the LCD device 100 when the driving voltage is applied to the liquid crystal layer.
The conventional transflective LCD device 100 is constructed such that a transmissive region and a reflective region are provided in a unit pixel. The transflective LCD device 100 includes a backlight reflector 110, a lower polarization layer 120, a lower retardation plate 130, a lower glass substrate 140 on which a reflector 144 is formed, a liquid crystal layer 150, an upper glass substrate 142, an upper retardation plate 132, an upper polarization layer 122, and a backlight lamp (not shown).
When the transflective LCD device 100 operates in a reflective mode, external light entered to a reflective region is reflected by the reflector 144 toward a front viewing direction. The external light entered to a transmissive region is reflected by the backlight reflector 110. Thereafter, a large quantity of the reflected light is further reflected by the reflector 144 and then blocked by the lower polarization layer 120, resulting in degradation of the light efficiency. When the transflective LCD device 100 operates in a transmissive mode, light from the backlight lamp is transmitted toward a front viewing direction of a transmissive region. However, light reflected by the reflector 144 at the reflective area is blocked by the lower polarization layer 120, resulting in degradation of the light efficiency. The lowered light efficiency deteriorates the transmissive luminance and reflectivity of the LCD device.